Recently, scientists said in a paper published before, try ultra fast laser writing in silicon, femtosecond laser in the structure to bulk silicon processing problem has been a breakthrough, the extreme NA pulse can achieve sufficient ionization breaking of chemical bonds in silicon laser allowed, leads to the change of permanent silicon materials structure.
Since the late 90s, researchers have been writing ultrashort pulses of femtosecond lasers into bulk materials with wide bandgap, which are usually insulators. But so far, the precision ultrafast laser pointer writing is still impossible for materials with narrow band gap, such as silicon and other semiconductor materials. People have been working to create more conditions for the application of 3D laser writing in Silicon Photonics and the study of new physical phenomena in semiconductors, thereby expanding the huge market for silicon applications.
In this experiment, scientists have found that femtosecond laser can not deal with bulk silicon even if the laser energy is increased to the maximum pulse intensity of technology. However, when femtosecond laser is replaced by ultrafast laser, there is no physical limitation in induced bulk silicon structure operation. They also found that the laser energy must be transported in a fast way in order to minimize the loss of nonlinear absorption. The original problem encountered in the previous work stems from the small numerical aperture (NA) of the laser, which is the angle range that can be projected when laser transmission is focused. The researchers solved the numerical aperture problem by using silicon spheres as solid immersion media. When the laser is focused at the center of the sphere, the silicon sphere completely suppresses the refraction and greatly increases the numerical aperture, thus solving the problem of silicon photon writing.
In fact, 3D green laser pointer writing in silicon photonic applications may greatly change the design and fabrication methods in the field of silicon photonics. The silicon photonics is regarded as the next revolution, affects the laser in the final data processing speed of the chip level, develop the 3D laser writing technology opens the door to the new world for microelectronics.